Early symptoms of diabetes, especially type 2 diabetes, can be subtle or seemingly harmless — that is, if you even have symptoms at all. Over time, however, you may develop diabetes complications, even if you haven't had diabetes symptoms.

In the United States alone, more than 8 million people have undiagnosed diabetes, according to the American Diabetes Association. But you don't need to become a statistic. Understanding possible diabetes symptoms can lead to early diagnosis and treatment — and a lifetime of better health. If you're experiencing any of the following diabetes signs and symptoms, see your doctor.

Excessive thirst (also called polydipsia) and increased urination (also known as polyuria) are classic diabetes symptoms.

When you have diabetes, excess sugar (glucose) builds up in your blood. Your kidneys are forced to work overtime to filter and absorb the excess sugar. If your kidneys can't keep up, the excess sugar is excreted into your urine, dragging along fluids from your tissues. This triggers more frequent urination, which may leave you dehydrated. As you drink more fluids to quench your thirst, you'll urinate even more.

You may feel fatigued. Many factors can contribute to this. They include dehydration from increased urination and your body's inability to function properly, since it's less able to use sugar for energy needs.

Weight fluctuations also fall under the umbrella of possible diabetes signs and symptoms. When you lose sugar through frequent urination, you also lose calories. At the same time, diabetes may keep the sugar from your food from reaching your cells — leading to constant hunger. The combined effect is potentially rapid weight loss, especially if you have type 1 diabetes.

Left untreated, diabetes can cause new blood vessels to form in your retina — the back part of your eye — and damage established vessels. For most people, these early changes do not cause vision problems. However, if these changes progress undetected, they can lead to vision loss and blindness.

Doctors and people with diabetes have observed that infections seem more common if you have diabetes. Research in this area, however, has not proved whether this is entirely true, nor why. It may be that high levels of blood sugar impair your body's natural healing process and your ability to fight infections. For women, bladder and vaginal infections are especially common.

Excess sugar in your blood can lead to nerve damage. You may notice tingling and loss of sensation in your hands and feet, as well as burning pain in your arms, hands, legs and feet.

Diabetes may weaken your ability to fight germs, which increases the risk of infection in your gums and in the bones that hold your teeth in place. Your gums may pull away from your teeth, your teeth may become loose, or you may develop sores or pockets of pus in your gums — especially if you have a gum infection before diabetes develops.

If you notice any possible diabetes signs or symptoms, contact your doctor. The earlier the condition is diagnosed, the sooner treatment can begin. Diabetes is a serious condition. But with your active participation and the support of your health care team, you can manage diabetes while enjoying an active, healthy life.

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